Background and History

IGO acquired the Long Operation, from BHP Billiton Nickel West Pty Ltd (formerly WMC Resources Ltd) in September 2002. The mine was successfully re-commissioned in October 2002 and has operated successfully and safely since then until 31 May 2018.

Since October 2002, IGO has produced approximately 137,000t contained nickel through to June 2018.

IGO was successful in identifying additional mineralisation at Long through continued investment in brownfields exploration, with the discovery of the McLeay (2005) and Moran (2008) ore bodies. Long commenced Care and Maintenance in June 2018 with the intention of continuing exploration to identify potential step change opportunities at Long.

Geology

The Long Operation comprises approximately 1,257km2 of tenements stretching 7.5km in strike length along the eastern flank of the Kambalda Dome in the South-Central portion of the Archaean Norseman-Wiluna Greenstone belt of the Yilgarn Craton.

The Kambalda Dome is a double-plunging antiform with a core of granodiorite flanked by meta-tholeiitic basalt which is overlain by komatiite and intercalated chemical sediments. The host rocks and associated contacts have been subjected to lower amphibolite metamorphism, structural modification, and intrusion by multiple felsic to intermediate igneous dykes.

The “world class Kambalda Sulphide Nickel” orebodies are associated with Achaean ultramafic lava channels where molten liquid nickel sulphides pooled at topographic lows along the komatiite channel. Subsequent folding has rotated the channels from 30° to vertical dip to the east, 10° plunge to the south as well as resulting in the remobilisation of some of the original sulphides into new structurally imposed positions. The sulphidic nickel ore bodies are narrow, ribbon like accumulation of massive to semi-massive sulphides to disseminated sulphide ore up to 12m thick.

Near Mine Exploration

A number of conceptual targets have been identified at Long and IGO’s intention is to drill these through FY19.

Care & Maintenance

IGO is actively maintaining the operation during care & maintenance to ensure its remains in a state of readiness for a number of options such as re-entry, exploration, exploitation and / or rehabilitation.

Whilst in care & maintenance, IGO will continue to dewater the underground mine, maintain surface and underground infrastructure, and undertake earthworks to ensure public safety and minimise environmental impacts.

Progressive Rehabilitation

IGO is also taking this opportunity to progressively rehabilitate some of the legacy landforms on the site including the old tailings storage facilities and waste (mullock) rock dump.